The Siau Island tarsier is a nocturnal primate from Siau Island, Indonesia. Its facial markings and a tuft at the end of its tail are described in the species account.
The account describes its fur and facial markings, and a tuft at the end of its sparsely furred tail.
Researchers observed very small social groups. Sleeping sites were high and difficult to reach, which may help the tarsiers avoid predators.
An extinction-risk assessment has not been added yet.